Vibration-damped tubular casing

ABSTRACT

The noise generated in a tubular casing such as the bolster casing of a textile spindle assembly is appreciably diminished by coating the outer surface of the casing with a viscoelastic material and adhering a rigid sheet to the viscoelastic material. The rigid sheet forms a discontinuous cylinder with at least one gap extending over the full length thereof.

United States Patent 1151 3,695,024 Tsunoda 1 Oct. 3, 1972 [54] VIBRATION-DAMPED TUBULAR 3,438,191 4/1969 Kuznetsov et al. ..57/135 CASING I FOREIGN PATENTS OR APPLICATIONS [72] Inventor: Kenneth Tsunoda, 625 D Closter k Road, c 07 24 1,044,688 11/1958 Germany ..57/135 237,037 7 1969 U.S.S.R. ..57 l 22 Filed: May 25,1971

[21] Appl. No.: 146,697 Primary Examiner-Wemer H. Schroeder Attorney-Paul W. Garbo [52] US. Cl ..57/130 511 1111.0. ..00111 7/12 [571 ABSTRACT of Search ..57/75, 77, The noise generated in a tubular casing u h as th 57/130,131, 132,133, 134,135, 13 bolster casing of a textile spindle assembly is ap- 74/574 preciably diminished by coating the outer surface of the casing with a viscoelastic material and adhering a [56] References cued rigid sheet to the viscoelastic material. The rigid sheet D STATES PATENTS forms a discontinuous cylinder with at least one gap UNITE extending over the full length thereof. 2,463,484 3/1949 Gelpke ..57/129 3,088,268 5/ 1963 Holschlag et al. ..57/135 10 Claims, 5 Drawing Figures PATENTEDBW I91 3 B W il r/ I ILlXAiI 1.. it EXMIII. v v

INVENTO'R KENNETH TSUNODA AGENT VIBRATION-DAMPED TUBULAR CASING BACKGROUND OF INVENTION This invention relates to tubular casings for moving bolster casings which hold the rotary spindles are still a source of much noise requiring independent damping means.

Accordingly, the object of this invention is to provide improved tubular casings for moving elements, more particularly bolster casings for textile machines, which are vibration-damped and, therefore, acoustically deadened.

SUMMARY OF THE INVENTION In accordance with this invention, the vibrationdamping of a bolster casing is achieved by applying an adherent layer of viscoelastic material on the outer surface of the casing and bonding to the viscoelastic layer a discontinuous cylinder formed of a relatively rigid sheet. At least one narrow gap extends over the full length of the discontinuous cylinder.

The viscoelastic material may be any elastomeric material having high mechanical hysteresis or internal friction but low modulus of elasticity compared to the tubular body of the bolster casing and the relatively rigid sheet between which the viscoelastic material is disposed. The efficiency of damping depends not only on the energy dissipation capacity of the viscoelastic layer but also on the proper coupling of the tubular body, the viscoelastic material and the relatively rigid sheet or constraining layer so that the vibrating energy of the bolster casing is transferred to the viscoelastic layer and there dissipated as heat. Amorphous polymers or copolymers, such as natural or synthetic rubber, polyvinyl chloride or alcohol, polypropylene, polyurethane and the like are suitable viscoelastic materials for the purpose of this invention. Glycoldiisocyanate copolymers are particularly desirable for use as the viscoelastic layer.

Generally, it is advisable to make the thickness of the layer of viscoelastic material not morethan about half of the thickness of tubular body on which it is applied and not more than about the full thickness of the relatively rigid or stiff sheet which is bonded thereto. Generally, the rigid sheet has a thickness less than that of the tubular body of the bolster casing; in many cases, the rigid sheet is preferably not more than about half as thick as the tubular body. It is often preferable to make the combined thickness of the rigid sheet and the viscoelastic layer not more than about the thickness of the tubular body of the bolster casing.

The bolster casing is frequently made of ordinary 'steel although other metals and alloys may be used in generally made of steel or other metal or alloy. However, the rigid or stifi' sheet or constraining layer used to form the discontinuous cylinder may be made of other rigid materials such as ceramic products or hard plastics. I

The term discontinuous cylinder is used herein to connote that the cylinder attached to the layer of viscoelastic material adhering to the tubular body has at least one interruption or gap extending the full length of the cylinder. This cylinder may advantageously have two, three or more lengthwise gaps between two, three or more cylindrical segments which, desirably but not necessarily, are of equal size.

For a fuller understanding of the invention, illustrative embodiments will now be described in detail in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view, with the upper portion shown in cross-section, of an improved bolster casing of this invention;

FIG. 2 is a cross-sectional view of the bolster casing of FIG. 1 taken along the line 2-2 thereof;

FIG. 3 is a cross-sectional view, similar to FIG. 2, of a modified bolster casing;

FIG. 4 is a partial front view of the lower portion of another modified bolster casing; and

FIG. 5 is a partial front cross-sectional view of the upper portion of a conventional bolster casing modified pursuant to this invention.

DESCRIPTION OF PREFERRED EMBODIMENTS The improved bolster casing of FIGS. 1 and 2 has tubular body 1 with a closed lower end 2 and a thickened upper end portion 3 which has external screw threads 4 and which terminates in top flange 5. As known in the textile spindle art, a bolster casing is inserted in an opening in a spindle or bolster rail and a nut is then brought up from the bottom end of the bolster casing and screwed up the threaded upper end portion of the casing until the rail is firmly clamped between the top flange of the casing and the nut. Nut 6 of the bolster casing of this invention serves the same purpose of fastening the casing on a spindle rail.

Pursuant to this invention, the unthreaded portion of tubular body 1 is completely covered on its outer surface by adherent layer 7 of viscoelastic material and two equal cylindrical segments 8 of a relatively stiff sheet are bonded to the exposed surface of layer 7. The adjacent longitudinal edges of the two segments 8 are spaced from each other by a slight gap 9 so that segrnents 8 cannot come into rubbing contact when the bolster casing is vibrated.

FIG. 3 is similar to FIG. 2 but shows tubular body 1 and adherent layer 7 of viscoelastic material surrounded by three cylindrical segments 10 of a stiff sheet, which have their longitudinal edges separated from each other by narrow gaps l 1.

FIG. 4 shows a modification of the lower portion of FIG. 1 wherein a single discontinuous cylinder 12 of a relatively stiff sheet is helically wrapped on and bonded to layer 7 of viscoelastic material on the outer surface of tubular body 1. The stiff strip forming discontinuous cylinder 12 is helically wrapped with a small gap or clearance 13 between adjacent edges of the strip; gap

13 extends over the full length of discontinuous cylinder 12.

FIG. is similar to the upper portion of FIG. 1 but shows a conventional bolster casing modified in accordance with this invention. Tubular body 14 has only a slightly thickened upper end portion 15 with external screw threads 16 and terminates in top flange 17. Originally, a nut was slipped up tubular body 14 and screwed on portion 15 provided with threads 16. However, that original nut was replaced by nipple 18 which has both internal screw threads 19 matching threads 16 on slightly thickened portion 15 of the bolster casing and external screw threads 20 matching the threads in enlarged nut 21.

The unthreaded portion of tubular body 14 is coated on its outer surface with adherent layer 22 of viscoelastic material and discontinuous cylinder 23 of a stiff sheet is bonded to layer 22. Discontinuous cylinder 23 may be in the form of two or more cylindrical segments as shown in FIGS. 2 and 3 or in the form of a helically wrapped stiff strip as shown in FIG. 4.

It will be noted that nipple 18, which is screwed onto the bolster casing before viscoelastic layer 22 and discontinuous cylinder 23 are applied thereto, is of sufficient thickness that the diameter of the threaded hole in nut 21 is slightly larger than the outside diameter of discontinuous cylinder-23. Thus, nut 21 can pass freely over discontinuous cylinder 23 and can be screwed v onto nipple 18.

What is claimed is:

1. A vibration-damped tubular casing containing a movable member capable of causing vibration by its movement, which comprises a layer of viscoelastic material adherent to the outer surface of said casing, and a discontinuous cylinder formed of a relatively rigid sheet and having at least one gap extending the full length of said cylinder, said cylinder being bonded to said layer of viscoelastic material.

2. The vibration-damped tubular casing of claim 1 wherein the layer of viscoelastic material has a thickness of not more than about half of the thickness of said casing.

3. The vibration-damped tubular casing of claim 1 wherein the discontinuous cylinder is provided by at least two cylindrical segments that are separated from each other by small gaps extending the full length of said cylindrical segments.

4. The vibration-damped tubular casing of claim 1 wherein the discontinuous cylinder is made of metal, and the layer of viscoelastic material comprises a material selected from the group consisting of amorphous polymers and copolymers.

5. The vibration-damped tubular casing of claim 1 I f i iig fi ii ti rilllihg bolster casing of claim 6 wherein the discontinuous cylinder is provided by at least two metal cylindrical segments that are separated from each other by small gaps extending the full length of said cylindrical segments.

8. The vibration-damped bolster casing of claim 7 wherein the layer of viscoelastic material has a thickness of not more than about half of the thickness of the tubular body and comprises a material selected from the group consisting of amorphous polymers and copolymers.

9. The vibration-damped bolster casing of claim 7 wherein the combined thickness of the discontinuous cylinder and the layer of viscoelastic material is not more than about the thickness of the tubular body.

10. The vibration-damped bolster casing of claim 9 wherein the upper end portion of the tubular body is externally threaded and a metal nipple which is both internally and externally threaded is screwed onto the threaded upper end portion of said tubular body, said nipple having a thickness at least slightly greater than the combined thickness of the discontinuous cylinder and the layer of viscoelastic material. 

1. A vibration-damped tubular casing containing a movable member capable of causing vibration by its movement, which comprises a layer of viscoelastic material adherent to the outer surface of said casing, and a discontinuous cylinder formed of a relatively rigid sheet and having at least one gap extending the full length of said cylinder, said cylinder being bonded to said layer of viscoelastic material.
 2. The vibration-damped tubular casing of claim 1 wherein the layer of viscoelastic material has a thickness of not more than about half of the thickness of said casing.
 3. The vibration-damped tubular casing of claim 1 wherein the discontinuous cylinder is provided by at least two cylindrical segments that are separated from each other by small gaps extending the full length of said cylindrical segments.
 4. The vibration-damped tubular casing of claim 1 wherein the discontinuous cylinder is made of metal, and the layer of viscoelastic material comprises a material selected from the group consisting of amorphous polymers and copolymers.
 5. The vibration-damped tubular casing of claim 1 wherein the discontinuous cylinder has a thickness less than that of said casing, and the layer of viscoelastic material has a thickness not more than about the full thickness of said cylinder.
 6. A vibration-damped bolster casing for a rotary spindle, which comprises a metal tubular body, a layer of viscoelastic material adherent to the outer surface of said tubular body, and a discontinuous cylinder formed of a relatively rigid sheet and having at least one gap extending the full length of said cylinder, said cylinder being supported in contact with substantially only said layer of viscoelastic material.
 7. The vibration-damped bolster casing of claim 6 wherein the discontinuous cylinder is provided by at least two metal cylindrical segments that are separated from each other by small gaps extending the full length of said cylindrical segments.
 8. The vibration-damped bolster casing of claim 7 wherein the layer of viscoelastic material has a thickness of not more than about half of the thickness of the tubular body and comprises a material selected from the group consisting of amorphous polymers and copolymers.
 9. The vibration-damped bolster casing of claim 7 wherein the combined thickness of the discontinuous cylinder and the layer of viscoelastic material is not more than about the thickness of the tubular body.
 10. The vibration-damped bolster casing of claim 9 wherein the upper end portion of the tubular body is externally threaded and a metal nipple which is both internally and externally threaded is screwed onto the threaded upper end portion of said tubular body, said nipple having a thickness at least slightly greater than the combined thickness of the discontinuous cylinder and the layer of viscoelastic material. 